We have identified three genes whose cognate RNAs are growth regulated and are inducible in quiescent cells by platelet-derived growth factor and serum. Although these three genes are inducible by PDGF or serum, their response to other mitogenic agents varies. In addition, they are all inducible in the presence of high concentrations of cycloheximide (which means that they are primary responders), they are transcriptionally regulated, and they appear to be overexpressed in certain forms of human myeloid leukemias. They constitute, therefore, an interesting set of genes in which one could study the regulation of expression of growth regulated genes. The purpose of this application is to extend our previous studies on these three growth regulated genes and, more specifically, to characterize them structurally and to identify their regulatory elements. Once their regulatory elements are identified we hope to be able to characterize them both structurally and functionally. While this characterization is in progress we will also attempt to obtain in bacteria their respective proteins.